HCV infection is an increasingly important clinical problem in patients infected with HIV. In HIV-uninfected patients with acute HCV infection, the presence of vigorous T-cell proliferative responses to HCV proteins is associated with normalization of serum transaminase levels and viral clearance. Furthermore, early results suggest IL-2 may improve transaminase levels in HCV/HIV patients. These observations provide the rationale for an immune-based therapeutic approach to HCV/HIV coinfection. This study explores the use of initial immunostimulatory therapy with IL-2 followed by the addition of antiviral therapy with PEG-IFN alfa-2b and RBV, as a possible synergistic approach to treatment.